Sea Horse 18hp ignition help **FINISHED**

[Drowned Rat]

Hi guys. This is a 1957 18hp Johnson. Can someone please tell me why the armature plate would move up and down? It moves about 1/4 inch up and down when you grab it. Are there screws or something that have come loose under the flywheel?

Thanks!

 

[F_R]

Re: Sea Horse 18hp ignition help

Re: Sea Horse 18hp ignition help

Slight movement is not unusual. Excessive movement might mean a broken armature plate (center bushing broken loose from the aluminum). Or it could mean the retainer plate is upside down. Remove the armature plate, you will find a brass retainer ring, remove that and you will find the retainer plate I'm speaking of. The flat side goes up.

 

[Drowned Rat]

Re: Sea Horse 18hp ignition help

Re: Sea Horse 18hp ignition help

Alright, thanks FR.

 

[Drowned Rat]

Re: Sea Horse 18hp ignition help

Re: Sea Horse 18hp ignition help

Okay, I've got it running, but I have a couple of questions. It starts very easily with the choke pulled, but the motor revs to it's limit even with the throttle all the way down. As soon as you push in the choke, it throttles down and is okay. It shouldn't do this with the choke out should it? The second thing is. The idle is way too high. I don't have a tach, but it's probably around 2000RPM with the throttle rolled all the way down. How do you adjust the idle speed on these. The book doesn't show how it's done. Otherwise it runs perfectly. Any ideas? Thanks for the help.

 

[F_R]

Re: Sea Horse 18hp ignition help

Re: Sea Horse 18hp ignition help

Nylon screw #107 on the throttle gear controls the idle speed (rpm).

Also check the carb / spark advance sync. There is a mark on the brass cam under the armature plate. When that mark is centered on the rubber roller, the carb throttle is supposed to just be at the point of starting to open. Adjust by loosening the screw and move cam in or out as nedded.

The choke does have a throttle kicker that partally opens the carb throttle shaft when choke is pulled.

 

[F_R]

Re: Sea Horse 18hp ignition help

Re: Sea Horse 18hp ignition help

The dreaded red x Trying that again,

 

[Drowned Rat]

Re: Sea Horse 18hp ignition help

Re: Sea Horse 18hp ignition help

Got it FR, thanks again. Now that I think about it, the choke has two positions. When you pull it out half way, it doesn't advance the throttle shaft.

Thanks for the diagram, I never would have found the idle screw.

Well, I think I'm done for a while, shouldn't have to bug you anymore. Thanks for all the help and have a great day.

DR

 

[Drowned Rat]

Re: Sea Horse 18hp ignition help *Finished*

Re: Sea Horse 18hp ignition help *Finished*

Well, here it is after the rebuilds and clearly amateur paint job. I know the decal is the wrong one, but it was cheap and I don't care that much. It'll still look good on the water I think.

The photos don't show it, but the red is a metallic garnet red. It really shines in the sun. It runs really good too!8) Now I need a new project. These are fun.

 

[steelespike]

Re: Sea Horse 18hp ignition help **FINISHED**

What a great job, congratulations!

 

[tmcalavy]

Re: Sea Horse 18hp ignition help **FINISHED**

SWEET...how'd you get the throttle/tiller grip so clean/white? I have done one also and it's the only part that seems dingy after the paint job.

 

[Drowned Rat]

Re: Sea Horse 18hp ignition help **FINISHED**

Thanks guys! tm, simple green and a scour pad cleaned it right up.

 

[BoatBuoy]

Re: Sea Horse 18hp ignition help **FINISHED**

Looks great. I'm a bit partial to '56's since I did a Javelin last year. What kind of paint did you use? Peter McDowell?